Braking means



Feb. 11, 1936. J. DESSART 2,030,784

BRAKING MEANS Filed July so, 1932 I am Jea/z Fess-art Patented Feb. 11, 1936 UNITED STATES BRAKING MEANS Jean Dessart, Brussels, Belgium, assignor to Bendix Products Corporation, a corporation of Indiana Application Jilly so, 1932, Serial No. 626.630 In Belgium August 1, 1931 2 Claims. (01. 188-3) My invention has for its object a device for braking towed vehicles by means of an auxiliary power fluid brake operated by fluid below or above atmospheric pressure, wherein the auxiliary pow- 5 er fluid brake is actuated by a piston or-other convenient member connected to the brake oper- .ating transmission by means of suitable connections permitting a movement of said piston relatively to the said brake transmission, said relative movement being utilized for controlling the valves of the brake distributor. Thus the braking effect will be a function of the displacements -of the actuating member. I

The accompanying diagrammatical drawing shows by way of example a construction according to my invention.

The device illustrated comprises: the vacuum pipe I connected with the suction source of the engine of the towing or motor vehicle through 20 the main reservoir 22 and a check valve 23, an auxiliary reservoir 2 connected with the vacuum pipe I through a check valve 3, a cylinder 4 connected with the vacuum pipe I and containing a piston 5 and a spring 5. The piston 5 is connected through link 5 to the point It of a lever I linked at 9 to a lever III and mounted to oscillate at III" on spindle I0 rigid with a stationary part of the structure. The end III" of the said lever IIl is connected to a piston II mounted in a servo-motor cylinder I4, the point I 5 of lever I 0 being connected through link I5 to the lever I5 forming part of the brake rodding. Oneend of the lever I is provided with an opening I! surrounding the spindle III and with 5 a limited play relative to said spindle. The,le-

ver' 1 is.connected at I througha' link 1 to the point 8 of a lever 8 pivotally mounted at 8' and controlling a distributor including valves I2 and 3. v 40 The control through the three-way cock hereinafter referred to permits the brake pipe I in one position to be in communication with the atmosphere through pipe 30, in another position to be in communication with the reservoir 22 and 45 in a third or lapped position cutting ofi' both the atmosphere and vacuum cylinder. In the first position of the valve, atmospheric air is admitted to operate the device in a manner to be later described; in the second position, the brake pipe is open'to the suction or vacuum to release the brakes; and in the third position the then condition of the structure is maintained and the brakes are held.

The springli of the auxiliary cylinder 4 is so 55 calculated as to be compressed by the piston 5,

when the vacuum in the brake pipe is at its maximum value.

When the piston 5 is at the right hand end of its stroke the brakes are in the released position. In this position the effect of the suction on the piston 5 is equal to the tension of the spring 6.

Thus, the displacements of the piston 5 in the cylinder 4 will control the operation of the brake of the towed vehicle, said displacements being in turn controlled by the driver of the towing or 10 motor vehicle.

To obtain a displacement of the piston 5, the driver, by means of a three way'cock 24 allows a certain quantity of air to enter the brake pipe I. Thereupon, the check valve 3 is pressed against 5 its seat by the difl'erence of pressure between the brake pipe I and the auxiliary reservoir 2; at the same time the vacuum in the cylinder 4 is reduced and the piston 5 moves towards the left under the action of the expanding spring 5, until 20 the tension of this spring will again become equivalent to the pull exerted on said piston by the vacuum. This movement of the piston is effeetive first in closing the air valve I2, and then in opening the valve I3, thus connecting the vac- 25 uum brake cylinder I2 with the auxiliary reservoir 2. Hence, the piston I I moves towards the.

left, taking with it the transmission link I5, thereby actuating the brakes. The resulting displacement of the brake transmission causes the lever I 30 to rock around the centre I5 thus returning the eye. II to its central position or the one in which both valves I2--I3 are closed. Thus, the position of piston II will be a function of that of the piston 5 while the position of the latter will be a function of the suction value in the brake pipe I. The suction value in the brake pipe may be'controlled by the driver at will.

Should the driver desire to increase the braking effect, he would allow a fresh quantity of 40 air to-enter the brake pipe I, when the described cycle will be repeated.

To release the brakes, the driver only needs to increase the vacuum in the brake pipe, when results contrary to those described will be obtained.

The device according to my invention has the following advantages:

First. Progressivity in applying and in releasing the brakes.

Second. The position of the brakes depends upon that of the actuating member, the latter position being a function of the vacuum value in thebrake pipe.

Third. The brake transmission lever allows for 5.5

may be arranged to be operated by air under pressure.

WhatIclaim is: r 1. In a braking means for controlling the brakes 01' a vehicle being towed from a towing vehicle, comprising a reservoir on a towed vehicle, a power cylinder on a towed vehicle, a

distributor controlling communication between the reservoir and power cylinder, a lever for op-. erating the distributor, a second lever for actuating the brakes, the first mentioned lever being pivotally supported by the second lever and having limited free movement relative thereto, an auxiliary cylinder, a piston in said cylinder connected to said first mentioned lever, a spring in the auxiliary cylinder for operating the piston in one direction, a suction pipe communicating with said cylinder, the auction in said pipe operating on the piston in the auxiliary cylinder in opposition to the spring therein, and a pipe connection between the suction pipe and the reservoir.

2. In a braking means for controlling the brakes of a towed vehicle from a towing vehicle, comprising a main vacuum reservoir on a towing vehicle in communication with the intake manifold of the engine, a suction brake pipe connnecting said reservoir to an auxiliary vacuum reservoir on a towed vehicle, a. check valve for said reservoir, a manually operable valve in the brake mine, a power-cylinder on the towed vehicle, a

distributor controlling communication between the reservoir and power cylinder, a lever for operating the distributor, a second lever for actuating the'brakes, the first mentioned lever being pivotally supported by the second lever and having limited play relative thereto, means respone sive to the degree of vacuum in the suction pipe and to the position of said levers to actuate the distributor and maintain the brake rodding in a given position, and means provided on a towing vehicle to control the degree of vacuum in said suction pipe.

. JEAN DESSART. 

